Kako projektorji projicirajo črno (preprosta razlaga)
Kot ste se naučili pri pouku naravoslovja v petem razredu, črna pravzaprav ni odsev svetlobe, temveč odsotnost bele barve. Torej, kako projektorji projicirajo črno na zaslon?
Projektorjem ni treba odbijati svetlobe, da projicirajo črno na zaslon. Projektorji projicirajo črno tako, da je sploh ne projicirajo. Tehnično torej projektorji ne projicirajo črne barve.
Preberite tudi:Ali bo projektor deloval na sivih ali črnih stenah?
Ste zmedeni? V tem članku se pogovorimo o ironiji projekcije črne barve in o tem, kako lahko naredimo črno barvo vašega projektorja še bolj črno.
Oglejte si moja najboljša priporočila za projektorje.
Kako projektorji projicirajo črno (ali jih?)
Kot smo že omenili, da projektorji projicirajo nazaj, jih sploh ne bodo morali projicirati. To pomeni, da se črna barva vsakega projektorja močno razlikuje glede na različne dejavnike.
Kasneje bomo razpravljali o tem, kako ustvariti boljše črne barve za vaš projektor. Za zdaj se poglobimo in se poglobimo v to, kako vaš projektor ustvari črno ali iluzijo črne.
Kako vidimo barvo?
Ste že kdaj razmišljali o tem, kako naše oči absorbirajo barve in zakaj so nekateri predmeti rdeči in nekateri modri? No, vse se začne z znanostjo o beli svetlobi.
Bela svetloba je rezultat kombinacije vseh barv vidnega barvnega spektra.
Zaradi te lastnosti bele lahko domnevamo, da bela svetloba vsebuje vse barve (razen črne, ki tehnično ni barva, ampak odtenek).
Ko bela svetloba zadene predmet, se ta predmet odbije ali absorbira. Barva se odbija in ne absorbira v barvi, ki jo vidimo.
Ko vidimo rdečo v jabolku, tehnično ne vidimo rdeče v jabolku, ampak rdečo, ki jo odseva jabolko.
Jabolko absorbira vse barve bele svetlobe razen rdeče, zato čepnice v očesu (tri vrste očesnih stožcev:modra, zelena in rdeča), ki so namenjene zaznavanju rdeče svetlobe, pošiljajo signale očesnim možganom, da vidi rdeče.
V bistvu torej, ko vidimo rdeče jabolko, rdeča dejansko ni znotraj jabolka, ampak je barva, ki je jabolko ne odseva (torej tehnično gledano jabolko ni rdeče, vendar jabolko odseva rdečo barvo).
Projekcija črne
Ko slišite, da so črni nasprotje belih, so tehnično točni! Če je bela kombinacija vseh barv, je črna odsotnost vseh barv in se zgodi, ko je vsa svetloba absorbirana in se nobena ne odbije.
Ker projektorji temeljijo na svetlobi, ne morejo projicirati odtenka, ki bi predstavljal odsotnost svetlobe. To ne bi bilo le ironično, ampak tudi znanstveno nemogoče. Zato projektorji ne projicirajo črne barve, da bi stvari poenostavili.
Zakaj je razmerje med projektorjem in črno zapleteno
Ker projektorji ne projicirajo črne barve, je črna, ki jo vidite na projekciji, močno odvisna od številnih spremenljivk. Izboljšanje kontrasta vašega projektorja je nekaj, česar se bomo lotili kasneje.
V tem delu članka pa se bomo lotili spremenljivk, ki vplivajo na črno barvo projektorjev.
Človeške oči so zapleten par mesa. They are not only very intricate, but together with the brain, they fill their physical limitations with the brain’s cognitive abilities (just like how smartphones have AI post-processing built-in on their cameras).
Our eyes see colors relative to the colors in proximity to them. It means that if a very dark color is put on a sea of white, it may seem even darker than it is. Take the image below as an example.
Image credits:Public Domain, Christopher S. Baird
Notice the two spaces surrounding the dots on the image. Although one seems lighter and the other seems darker, both are the same hue.
Now you may ask how this applies to projectors specifically. If the projected image contains blacks surrounded by many lighters, vibrant colors, it may seem dark. However, if the projected image’s black images are next to relatively dark images, it may not seem dark.
The surface is essential.
Since blacks on a projector are not reflected, the blacks on projected images will vary significantly concerning their projected surface.
It means that if a projector projects at a highly light surface, the black may not be very black as expected. On the contrary, if the projector projects at something dark like a black-painted wall, the blacks will be extremely dark.
For reference, let us refer to the image below. Ideally, a projector would project perfect blacks like the image on the left.
However, in practice, most projector’s blacks will largely depend on how the projected surface looks and will look like the one projected on the right.
Image credits:Public Domain, Christopher S. Baird
The mystery of black:how does a projector make black?
Sadly, a projector does not actually “make” the color black. Since there is no such thing as black-colored light, projecting black is impossible.
Some projectors mix colors to produce a brown-like color used to represent black. Although not wholly black, our eyes perceive it as black nonetheless.
And now you know why a cinema turns the lights off – so the white screen is black in the absence of light. It makes the black items on film truly more black.
Three Frequently Asked Questions About The Projection Of Black
Should I choose a black or white screen?
For better contrast (to display better blacks), you should opt for a black screen. For a brighter image, you should opt for a white screen.
If you are watching in a dark environment, you should consider using a black screen since visibility and brightness are not an issue in light-restricted areas.
Are there HDR projectors?
Yes, there are HDR projectors. However, for an optimal experience, you should still curate your room to be built projector-first (in other words, consider the use of a projector when designing a room at all times).
What should I do to get a better quality image with my projector?
Ensuring that your projector is HDR, has the right amount of brightness, and has the right amount of resolution is critical.
Additionally, projectors are heavily affected by outside influence, so you should make your viewing room as dark as possible. Using black screens and having high-quality HDR video is also essential.
Sources
- https://wtamu.edu/~cbaird/sq/2015/06/16/how-do-projectors-project-the-color-black/
- https://www.amnh.org/ology/features/stufftodo_einstein/see_color.php
- https://www.pantone.com/articles/color-fundamentals/how-do-we-see-color
- https://wtamu.edu/~cbaird/sq/2015/06/16/how-do-projectors-project-the-color-black/
- https://pointerclicker.com/how-do-projectors-project-black/